I. Field
The present disclosure relates generally to communication, and more specifically to techniques for transmitting control information in a wireless communication system.
II. Background
Wireless communication systems are widely deployed to provide various communication content such as voice, video, packet data, messaging, broadcast, etc. These wireless systems may be multiple-access systems capable of supporting multiple users by sharing the available system resources. Examples of such multiple-access systems include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, Orthogonal FDMA (OFDMA) systems, and Single-Carrier FDMA (SC-FDMA) systems.
In a wireless communication system, a Node B may transmit traffic data to a user equipment (UE) on the downlink and/or receive traffic data from the UE on the uplink. The downlink (or forward link) refers to the communication link from the Node B to the UE, and the uplink (or reverse link) refers to the communication link from the UE to the Node B. The UE may send channel quality indicator (CQI) information indicative of the downlink channel quality to the Node B. The Node B may select a rate or transport format based on the CQI information and may send traffic data at the selected rate or transport format to the UE. The UE may send acknowledgement (ACK) information for traffic data received from the Node B. The Node B may determine whether to retransmit pending traffic data or to transmit new traffic data to the UE based on the ACK information. It is desirable to reliably send ACK and CQI information in order to achieve good performance.